/*
 * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 *
 */
package javax.swing.plaf.nimbus;

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.Transparency;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.awt.image.ColorModel;

/**
 * EffectUtils
 *
 * @author Created by Jasper Potts (Jun 18, 2007)
 */
class EffectUtils {

  /**
   * Clear a transparent image to 100% transparent
   *
   * @param img The image to clear
   */
  static void clearImage(BufferedImage img) {
    Graphics2D g2 = img.createGraphics();
    g2.setComposite(AlphaComposite.Clear);
    g2.fillRect(0, 0, img.getWidth(), img.getHeight());
    g2.dispose();
  }

  // =================================================================================================================
  // Blur

  /**
   * Apply Gaussian Blur to Image
   *
   * @param src The image tp
   * @param dst The destination image to draw blured src image into, null if you want a new one
   * created
   * @param radius The blur kernel radius
   * @return The blured image
   */
  static BufferedImage gaussianBlur(BufferedImage src, BufferedImage dst, int radius) {
    int width = src.getWidth();
    int height = src.getHeight();
    if (dst == null || dst.getWidth() != width || dst.getHeight() != height || src.getType() != dst
        .getType()) {
      dst = createColorModelCompatibleImage(src);
    }
    float[] kernel = createGaussianKernel(radius);
    if (src.getType() == BufferedImage.TYPE_INT_ARGB) {
      int[] srcPixels = new int[width * height];
      int[] dstPixels = new int[width * height];
      getPixels(src, 0, 0, width, height, srcPixels);
      // horizontal pass
      blur(srcPixels, dstPixels, width, height, kernel, radius);
      // vertical pass
      //noinspection SuspiciousNameCombination
      blur(dstPixels, srcPixels, height, width, kernel, radius);
      // the result is now stored in srcPixels due to the 2nd pass
      setPixels(dst, 0, 0, width, height, srcPixels);
    } else if (src.getType() == BufferedImage.TYPE_BYTE_GRAY) {
      byte[] srcPixels = new byte[width * height];
      byte[] dstPixels = new byte[width * height];
      getPixels(src, 0, 0, width, height, srcPixels);
      // horizontal pass
      blur(srcPixels, dstPixels, width, height, kernel, radius);
      // vertical pass
      //noinspection SuspiciousNameCombination
      blur(dstPixels, srcPixels, height, width, kernel, radius);
      // the result is now stored in srcPixels due to the 2nd pass
      setPixels(dst, 0, 0, width, height, srcPixels);
    } else {
      throw new IllegalArgumentException(
          "EffectUtils.gaussianBlur() src image is not a supported type, type=[" +
              src.getType() + "]");
    }
    return dst;
  }

  /**
   * <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by
   * the radius which must be greater than 0.</p> <p>The source and destination pixels arrays are
   * expected to be in the INT_ARGB format.</p> <p>After this method is executed, dstPixels contains
   * a transposed and filtered copy of srcPixels.</p>
   *
   * @param srcPixels the source pixels
   * @param dstPixels the destination pixels
   * @param width the width of the source picture
   * @param height the height of the source picture
   * @param kernel the kernel of the blur effect
   * @param radius the radius of the blur effect
   */
  private static void blur(int[] srcPixels, int[] dstPixels,
      int width, int height,
      float[] kernel, int radius) {
    float a;
    float r;
    float g;
    float b;

    int ca;
    int cr;
    int cg;
    int cb;

    for (int y = 0; y < height; y++) {
      int index = y;
      int offset = y * width;

      for (int x = 0; x < width; x++) {
        a = r = g = b = 0.0f;

        for (int i = -radius; i <= radius; i++) {
          int subOffset = x + i;
          if (subOffset < 0 || subOffset >= width) {
            subOffset = (x + width) % width;
          }

          int pixel = srcPixels[offset + subOffset];
          float blurFactor = kernel[radius + i];

          a += blurFactor * ((pixel >> 24) & 0xFF);
          r += blurFactor * ((pixel >> 16) & 0xFF);
          g += blurFactor * ((pixel >> 8) & 0xFF);
          b += blurFactor * ((pixel) & 0xFF);
        }

        ca = (int) (a + 0.5f);
        cr = (int) (r + 0.5f);
        cg = (int) (g + 0.5f);
        cb = (int) (b + 0.5f);

        dstPixels[index] = ((ca > 255 ? 255 : ca) << 24) |
            ((cr > 255 ? 255 : cr) << 16) |
            ((cg > 255 ? 255 : cg) << 8) |
            (cb > 255 ? 255 : cb);
        index += height;
      }
    }
  }

  /**
   * <p>Blurs the source pixels into the destination pixels. The force of the blur is specified by
   * the radius which must be greater than 0.</p> <p>The source and destination pixels arrays are
   * expected to be in the BYTE_GREY format.</p> <p>After this method is executed, dstPixels
   * contains a transposed and filtered copy of srcPixels.</p>
   *
   * @param srcPixels the source pixels
   * @param dstPixels the destination pixels
   * @param width the width of the source picture
   * @param height the height of the source picture
   * @param kernel the kernel of the blur effect
   * @param radius the radius of the blur effect
   */
  static void blur(byte[] srcPixels, byte[] dstPixels,
      int width, int height,
      float[] kernel, int radius) {
    float p;
    int cp;
    for (int y = 0; y < height; y++) {
      int index = y;
      int offset = y * width;
      for (int x = 0; x < width; x++) {
        p = 0.0f;
        for (int i = -radius; i <= radius; i++) {
          int subOffset = x + i;
//                    if (subOffset < 0) subOffset = 0;
//                    if (subOffset >= width) subOffset = width-1;
          if (subOffset < 0 || subOffset >= width) {
            subOffset = (x + width) % width;
          }
          int pixel = srcPixels[offset + subOffset] & 0xFF;
          float blurFactor = kernel[radius + i];
          p += blurFactor * pixel;
        }
        cp = (int) (p + 0.5f);
        dstPixels[index] = (byte) (cp > 255 ? 255 : cp);
        index += height;
      }
    }
  }

  static float[] createGaussianKernel(int radius) {
    if (radius < 1) {
      throw new IllegalArgumentException("Radius must be >= 1");
    }

    float[] data = new float[radius * 2 + 1];

    float sigma = radius / 3.0f;
    float twoSigmaSquare = 2.0f * sigma * sigma;
    float sigmaRoot = (float) Math.sqrt(twoSigmaSquare * Math.PI);
    float total = 0.0f;

    for (int i = -radius; i <= radius; i++) {
      float distance = i * i;
      int index = i + radius;
      data[index] = (float) Math.exp(-distance / twoSigmaSquare) / sigmaRoot;
      total += data[index];
    }

    for (int i = 0; i < data.length; i++) {
      data[i] /= total;
    }

    return data;
  }

  // =================================================================================================================
  // Get/Set Pixels helper methods

  /**
   * <p>Returns an array of pixels, stored as integers, from a <code>BufferedImage</code>. The
   * pixels are grabbed from a rectangular area defined by a location and two dimensions. Calling
   * this method on an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code> and
   * <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
   *
   * @param img the source image
   * @param x the x location at which to start grabbing pixels
   * @param y the y location at which to start grabbing pixels
   * @param w the width of the rectangle of pixels to grab
   * @param h the height of the rectangle of pixels to grab
   * @param pixels a pre-allocated array of pixels of size w*h; can be null
   * @return <code>pixels</code> if non-null, a new array of integers otherwise
   * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h
   */
  static byte[] getPixels(BufferedImage img,
      int x, int y, int w, int h, byte[] pixels) {
    if (w == 0 || h == 0) {
      return new byte[0];
    }

    if (pixels == null) {
      pixels = new byte[w * h];
    } else if (pixels.length < w * h) {
      throw new IllegalArgumentException("pixels array must have a length >= w*h");
    }

    int imageType = img.getType();
    if (imageType == BufferedImage.TYPE_BYTE_GRAY) {
      Raster raster = img.getRaster();
      return (byte[]) raster.getDataElements(x, y, w, h, pixels);
    } else {
      throw new IllegalArgumentException("Only type BYTE_GRAY is supported");
    }
  }

  /**
   * <p>Writes a rectangular area of pixels in the destination <code>BufferedImage</code>. Calling
   * this method on an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code> and
   * <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
   *
   * @param img the destination image
   * @param x the x location at which to start storing pixels
   * @param y the y location at which to start storing pixels
   * @param w the width of the rectangle of pixels to store
   * @param h the height of the rectangle of pixels to store
   * @param pixels an array of pixels, stored as integers
   * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h
   */
  static void setPixels(BufferedImage img,
      int x, int y, int w, int h, byte[] pixels) {
    if (pixels == null || w == 0 || h == 0) {
      return;
    } else if (pixels.length < w * h) {
      throw new IllegalArgumentException("pixels array must have a length >= w*h");
    }
    int imageType = img.getType();
    if (imageType == BufferedImage.TYPE_BYTE_GRAY) {
      WritableRaster raster = img.getRaster();
      raster.setDataElements(x, y, w, h, pixels);
    } else {
      throw new IllegalArgumentException("Only type BYTE_GRAY is supported");
    }
  }

  /**
   * <p>Returns an array of pixels, stored as integers, from a
   * <code>BufferedImage</code>. The pixels are grabbed from a rectangular
   * area defined by a location and two dimensions. Calling this method on
   * an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>
   * and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
   *
   * @param img the source image
   * @param x the x location at which to start grabbing pixels
   * @param y the y location at which to start grabbing pixels
   * @param w the width of the rectangle of pixels to grab
   * @param h the height of the rectangle of pixels to grab
   * @param pixels a pre-allocated array of pixels of size w*h; can be null
   * @return <code>pixels</code> if non-null, a new array of integers otherwise
   * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h
   */
  public static int[] getPixels(BufferedImage img,
      int x, int y, int w, int h, int[] pixels) {
    if (w == 0 || h == 0) {
      return new int[0];
    }

    if (pixels == null) {
      pixels = new int[w * h];
    } else if (pixels.length < w * h) {
      throw new IllegalArgumentException("pixels array must have a length" +
          " >= w*h");
    }

    int imageType = img.getType();
    if (imageType == BufferedImage.TYPE_INT_ARGB ||
        imageType == BufferedImage.TYPE_INT_RGB) {
      Raster raster = img.getRaster();
      return (int[]) raster.getDataElements(x, y, w, h, pixels);
    }

    // Unmanages the image
    return img.getRGB(x, y, w, h, pixels, 0, w);
  }

  /**
   * <p>Writes a rectangular area of pixels in the destination
   * <code>BufferedImage</code>. Calling this method on
   * an image of type different from <code>BufferedImage.TYPE_INT_ARGB</code>
   * and <code>BufferedImage.TYPE_INT_RGB</code> will unmanage the image.</p>
   *
   * @param img the destination image
   * @param x the x location at which to start storing pixels
   * @param y the y location at which to start storing pixels
   * @param w the width of the rectangle of pixels to store
   * @param h the height of the rectangle of pixels to store
   * @param pixels an array of pixels, stored as integers
   * @throws IllegalArgumentException is <code>pixels</code> is non-null and of length &lt; w*h
   */
  public static void setPixels(BufferedImage img,
      int x, int y, int w, int h, int[] pixels) {
    if (pixels == null || w == 0 || h == 0) {
      return;
    } else if (pixels.length < w * h) {
      throw new IllegalArgumentException("pixels array must have a length" +
          " >= w*h");
    }

    int imageType = img.getType();
    if (imageType == BufferedImage.TYPE_INT_ARGB ||
        imageType == BufferedImage.TYPE_INT_RGB) {
      WritableRaster raster = img.getRaster();
      raster.setDataElements(x, y, w, h, pixels);
    } else {
      // Unmanages the image
      img.setRGB(x, y, w, h, pixels, 0, w);
    }
  }

  /**
   * <p>Returns a new <code>BufferedImage</code> using the same color model
   * as the image passed as a parameter. The returned image is only compatible
   * with the image passed as a parameter. This does not mean the returned
   * image is compatible with the hardware.</p>
   *
   * @param image the reference image from which the color model of the new image is obtained
   * @return a new <code>BufferedImage</code>, compatible with the color model of <code>image</code>
   */
  public static BufferedImage createColorModelCompatibleImage(BufferedImage image) {
    ColorModel cm = image.getColorModel();
    return new BufferedImage(cm,
        cm.createCompatibleWritableRaster(image.getWidth(),
            image.getHeight()),
        cm.isAlphaPremultiplied(), null);
  }

  /**
   * <p>Returns a new translucent compatible image of the specified width and
   * height. That is, the returned <code>BufferedImage</code> is compatible with
   * the graphics hardware. If the method is called in a headless
   * environment, then the returned BufferedImage will be compatible with
   * the source image.</p>
   *
   * @param width the width of the new image
   * @param height the height of the new image
   * @return a new translucent compatible <code>BufferedImage</code> of the specified width and
   * height
   */
  public static BufferedImage createCompatibleTranslucentImage(int width,
      int height) {
    return isHeadless() ?
        new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB) :
        getGraphicsConfiguration().createCompatibleImage(width, height,
            Transparency.TRANSLUCENT);
  }

  private static boolean isHeadless() {
    return GraphicsEnvironment.isHeadless();
  }

  // Returns the graphics configuration for the primary screen
  private static GraphicsConfiguration getGraphicsConfiguration() {
    return GraphicsEnvironment.getLocalGraphicsEnvironment().
        getDefaultScreenDevice().getDefaultConfiguration();
  }

}
